Die casting machine pressure chambers



May 26, 1959 M. STERN 2,887,742

I DIE CASTING MACHINE PRESSURE CHAMBERS Filed Feb. 21, 1958 2Sheets-Sheet 1 270 1! I 290 W f 29/ I H "E rzw F5314 .Ffii F E INVENTOR.

MARC 5752M May 26, 1959 M. STERN DIE CASTING MACHINE PRESSURE CHAMBERSFiled Feb. 21. 1958 2 Sheets-Sheet 2 24 INVENTOR. --/20 MARC 5752 A 770NF) United States Patent DIE CASTING MACHINE PRESSURECHAMBERS MarcStern, Flint, Mich. I Application February 21, 1958', Serial No'. 716,'572 Claims. (Cl. 22-68) This invention relates to die casting machines;and in particular to improvements in die casting machine pressurechambers of the submerged type.

The present invention is an improvement over the die casting machinepressure chamber construction disclosed andclaimedin U.S. Patent No.2,786,247, issued March 26, 1957, to Marc Stern, the inventor'intheinstant case.

Conventional die casting machines of the type to which this inventionrelates are employed to injection mold low melting point alloy castings,which machines generally include a pressure chamber which is submergedinto a pot of molten metal wherein the said pressurechamber receives itscharge of molten metal by gravity. During the operating or injectionmolding cycle of; the die cast ing machine, molten metal is forced fromthe pressure chamber into a die by means of a power actuated'plunger orpiston operating in the pressure chamber. After molten metal has beeninjected into the; die, the plunger retracts, and a newcharge ofmoltenmetal'flows fromthe pot into the pressure chamber filling; itpriorto the next operating cycle of the die casting machine. I

.Pressure chambers of the type presently in general use consist of acylinder having a plunger reciprocatingly mounted therein and agooseneck outlet extending from said cylinder and communicating betweenthe bottom of the said cylinder to the injection nozzle of the injectionmolding; machine. An inlet extends from near the top so that the moltenmetal flowing to the cylinder is always withdrawn from the pot at apoint somewhat below the upper level of molten metal therein; This, typeof pressure chamber is generally referred; to as a gooseneck,

deriving its name from the shape of its outlet. Such prior art structureis disclosed in Fig. 1 of U.S., Patent No. 2,145,956, issued February 7,1939, to Marc Stern, the inventor in the instant case.

Because of the high cost of the manufactureof high pressure resistantand porosity free gooseneck'type pressure chamber castings, and" thecost of machining and. maintaining gooseneck pressure chambers, and dueto; the

difficulty of handling gooseneck type pressure chambers, tov drain themolten metal therefrom whenever replacement.

or removing the same from the; pot becomes'necessary,

and because the plunger must be withdrawn from, thecylinder of thegooseneck before the gooseneck may be.

stresses occasioned during heating and'coolingof they molten metal, thepressure chamber and thenozzle arising Furthermore, the

from temporary suspensions of operation of the die casti'ng machine,which stresses ofttimes cause distortion and breakage ofvarious elementsof the pressure chamber.

With the foregoing in view, the primary object of the instant inventionis to provide an improved submerged type pressure chamber construction,for die casting ma: chines including-a molten metal pressure, delivery.unit consisting of a pressure chamber cylinder, and piston which. maybereadily placed into and removed from service in. the die castingmachine whereby to facilitate replacement thereof by like molten metaldelivery units of the same or different capacities with a minimum ofdiecasting'machine down'time. V 7

Another object of the invention is to provide an improved pressurechamber construction for die casting ma.. chines employing a readliyremovable molten, metal pressure delivery unit and mounting meanstherefor incorpo:

rating large anchorage and supporting areas to adequately absorb therepeated heavy thrusts occurring during the molten metal 'deliverycyclesof operation of the die casting machine whereby to eliminate the extreme,wear nor: mally encountered in the usual pin connected or hingedsupporting means generally employed in pressurechamber'construction.

A further object of the invention is to provide wedge lockimeans forholdingthe removable and replaceable, molten metal pressure deliveryunit in firm operating po-, sition, which wedge lock means may be lockedand un-. locked periodically or at the beginning and end of each. cycleof operation of'the die casting machine whereby to periodically orcyclically relieve the, pressure chamber elements of expansion andcontraction stresses, and thereby materially reduce the hazards ofpermanent dis: tortion or breakage ofthe pressure chamber elements.occasioned under the many heating and cooling, phases to which'they aresubjected during normal production die casting machine operation such asrepeated placement of the, die casting machine into and out of operationoccasioned'by breaks in continuity of production due to operator restperiods or die maintenance, and during re.-

placementof the molten metal pressure delivery unit by of the cylinderdownwardly into the pot of, molten metal like units of the same ordifferent capacity.

Other'objects of the invention will become apparent by reference to thefollowing detailed description taken in connection with the accompanyingdrawings, in which:

Fig. l is a side elevational view of a die casting machine pressurechamber embodying the inventiom portions beingbroken away to moreclearly illustrate the construction.

Fig. 2 is a view in perspective of the mounting bloclt s for mountingthe pressure chamber on the frame of a,

die casting machine.

Figs. 3, 4 and 5 are side and end elevational views of the wedge lockmember employed to removably fix the molten metal pressure delivery unitin operating position during the die casting cycle of operation of thedie'casting machine.

Fig. 6 is a horizontal sectional view taken on the the line 6-6 of Fig.l of the wedge'lock actuating mechanism fixed'on the mounting block andwith the wedge lock member disposed in its locked position.

Fig. 7 is a front elevational view of the die casting machine pressurechamber disclosed in Fig. 1 with the wedge lock actuating mechanismremoved and parts" broken away to more clearly illustrate theconstruction. Fig. 8 is a view in perspective of the bifurcated "cageelement employed to removably engage the pressure chamber cylinder ofthe molten metal pressure delivery unit.

Fig. 9 is a horizontal sectional view taken on the line 3 Fig. is ahorizontal sectional view taken on the line 10-10 of Fig. 7.

Figs. 11 and 12 are side and front elevational views of the molten metaldelivery unit preferably employed.

'Figs. 13 and 14 are side and front elevational views of an alternatemolten metal delivery unit construction wherein the disposition of thepressure chamber cylinder and the piston has been reversed.

Referring now to the drawings wherein like reference characters referto'like and corresponding parts throughout the several views, the diecasting pressure chamber 10 disclosed in Figs. 1-12, inclusive, for thepurpose of illustrating the invention consists of a molten metalpressure delivery unit 11 which includes a pressure chamber cylinder 12and piston 13 and means hereinafter described for removably mounting andreleasably fixing the said pressure delivery unit in operating positionon a die casting machine 14 and in the molten metal pot 15 thereof.

The usual die casting machine 14 includes at one end thereof a frameelement 16 into which the fixed and movable die elements 170 and 171 ofa partable die 17 is mounted. The fixed die element 170 is mounted onthe frame 16 opposite a nozzle opening 160 therein while the movable dieelement 171 is mounted on the die carrying ram 18 of the die castingmachine 14, which ram 18 is operated by hydraulic or mechanical means,not shown, to open andclose the partable'die 17 for removal of castingstherefrom. Molten metal 150 from the molten metal pot 15 is supplied tothe die 17 through a nozzle 19 communicating between the delivery neck132 of the piston 13 of the molten metal delivery unit 11- and the sprue1701 of the die 17 as indicated in Fig. l.

The die casting machine pressure chamber 10 includes a mounting block 20shown in Fig. 2 fixed in cantilever relationship on the frame 16 of thedie casting machine 14 as indicated in Fig. l. The said mounting block20 has a transversely dis osed U-shaped vertically disposed cavity 21therein at the top thereof over which is preferably mounted a doubleacting hydraulic cylinder 22 having a ram 23 extending downwardlytherefrom and reciorocable vertically in the said U-shapedcavity 21. Abifurcated ca e element '24 is fixed at its transversely disposed head240 on the threaded bottom end 230 of the ram 23 of the hydrauliccylinder 22 by a nut 25. The depending arms 241 of the said bifurcatedcage element 24 terminate in o positely and inwardly horizontallydisposed fingers 242 which removably engage the pressure chambercylinder 12 of the pressure delivery unit 11 at horizontally disposedslots 120 provided therein. With the foregoing construction. actuationof the hydraulic cylinder 22 in one direction causes its ram 23 to moveupwardly and move the bifurcated cage element 24 and the pressurechamber cylinder 12 upwardly from its position shown in Fi l, andsubsequent reversal of the hydraulic cylinder 22 returns the saidpressure chamber cylinder 12 to its initial position as shown.

The piston 13 of the molten metal pressure delivery unit 11 consists ofa hollow piston head 130 and a shank 131 thereabove terminating in acurved delivery neck 132, the said shank 131 having a passage 133therethrough preferably somewhat smaller than the cavity of the hollowpiston head 130 communicating between the hollow piston head 130 and asemispherical socket 1320 formed at the outlet end of the said curveddelivery neck 132. The fixed die element 170 of the partable die 17 hasa like semispherical socket 1700 at the outer end of the sprue 1701thereof. The nozzle 19 which communicates between the delivery neck 132of the piston 13 and the sprue 1701 of the die 17 is provided with alongitudinal passage 190 therethrough, and has semispherical ends whichseat in the semispherical sockets 1320 and 1700 of the piston 13 and die17 respectively i 4 the die casting machine pressure chamber 10 ashereinafter described.

The piston 13 is provided with a T-slide element 134 integral with thecurved delivery neck 132 of the said piston 13, disposed thereabove andparallel to the outlet end of the said delivery neck 132. The saidmounting block 20 of the die casting machine pressure chamber 10 isprovided with a horizontally disposed T-slot 201 which telescopinglyreceives the T-slide element 134 of the piston 13 so that thesemispherical socket 1320 at the outlet end of the curved delivery neck132 is in substantial alignment with the semispherical socket 1700 ofthe partable die 17.

A pair of anchor bars 26 extend forwardly outward from the frame 16 ofthe die casting machine 14 onto the threaded ends 260 of which arepositioned leaf springs 27. The said leaf springs 27 are preferablybowed at i 270 to contact the outer end of the vertically disposed shank1340 of the said T-slide element 134 formed integral with the curveddelivery neck 132 of the piston 13. Tightening of nuts 28 threaded onthe threaded ends 260 of the anchor bars 26 compresses the leaf Springs27 and urges the delivery neck socket 1320 of the piston 13 firmly intosealed relationship with one end of the nozzle 19 whereupon the otherend of the nozzle 19 is urged firmly into sealed relationship with thesocket 1700 of the partable die 17 as shown in Figs. 1 and 9.

The mounting block 20 is also provided with a sloping T-slot 202 intowhich a T-shaped wedge 29 shown in Figs. 3, 4 and 5 having a head 290and a shank 291 is telescoped. The said T-slot 202 is disposed justabove the T-slot 201 and communicates vertically therewith so that theshank 2910f the T-shaped wedge 29 will contact the top of the T-slideelement 134 of the piston 13 and firmly fix the said piston 13 independing relationship from the mounting block 20 of the die castingmachine pressure chamber 10. When the T-shaped wedge 29 is retracted,the piston 13 is supported in the T-slot 201 in the mounting block 20and is spring urged against the nozzle 19, the remaining connectionbetween the said piston 13 and the mounting block 20 having sufiicientplay to avoid the introduction of expansion and contraction stressestherebetween.

By advancing the T-shaped wedge 29, the piston 13 remains spring urgedagainst the nozzle 19, and, in addition, the remaining connectionbetween the said piston 13 and the mounting block 20 becomes locked-upfirmly so as to resist any tendency for the piston 13 to wobble in itssupport and part from the nozzle 19. Such lock-up of the piston 13 alsoresists any tendency of the nozzle 19 to part from the die 17 during thepressure delivery of molten metal by the molten metal pressure deliveryunit 11. Obviously, the retraction of the T-shaped Wedge 29 unlocks thepiston. 13 and allows play between the piston 13 and the block 20 torelieve expansion and contraction stresses in the die casting machinepressure cham ber 10.

The T-shaped wedge 29 may be moved into and out of its locked positionin the sloping T-slot 202 of the mounting block 20 against the top ofthe T-slide 134 of the piston 13 by such suitable means as a doubleacting hydraulic cylinder 30 supported on mounting bars 31 extend-.

ing outwardly from the mounting block 20 as best shown in Figs. 1 and 6.The ram 300 of the hydraulic cylinder 30 is threaded or otherwise fixedto the front end of the T-shaped wedge block 29 which is threaded at 292to accommodate the said ram 300.

By actuating the said cylinder 30 to advance the T- shaped wedge block29 before each molten metal delivery pressure stroke of the molten metaldelivery unit 11, and then actuating the said cylinder to retract thesaid T- shaped wedge block 29 after each return stroke of the saidmolten metal delivery unit 11, the die casting ma chine pressure chamberwill constantly accommodate when the molten metal delivery unit 11 is.assembled in 76 ite1f e pa n and n action ot its several ele eancltthereby eliminate any possibility of destruction of its elementsresponsive to expansion and contractiontstresses. Alternatively, thecylinder 30' may be omitted, and the T-shaped wedge block 29'may beurgedto its, advanced the improved die casting machine pressure chamber arein effect floatingly mounted on the die castingmachine several elementsthereof directly'in contact with molten metal during heating-up andcooling-down ofthe said pressure chamber 10,.the said pressure chamberlflbeing locked prior to die casting into an integral operating wholeresponsive to the movement of the wedge lock means. 29 into its lockedposition thereby fixing the otherwise floatingpiston 13 in respectto themounting block 20in the position to which the said floating piston 13 isspring urged by: the springs 27 as hereinbefore described.

As best shown in Figs. 1, 7, 11 and 12 the cylinder 12; of the moltenmetal pressure delivery unit 11 of the die castingv machine pressurechamber 10 is reciprocably mounted on the lower hollow piston head 130of the piston 13. The, said cylinder 12 has an inlet aperture 121therein suitably located. so that the said cylinder 12 will fill withmoltenmetal 150 each time; the said cylinder 12 is retractedby'thehydraulic cylinder'22 to its position shown in Fig. 1. Thesaidcylinder 12 is engaged for movement by the double actinghydraulic'cylinder22 by the fingers. 242 on the depending arms 241 ofthe bifurcated cage element 240 which is connected to the threaded end230 of theram 23 of the said hydraulic cylinder 22 by,a nut 25asthereinbefore described.

Figs. 13. and 14 show how the cylinder 12 and the pis ton 13 ofv themolten metal delivery unit 11 may be reversed, which is accomplishedby'constructing a molten metal delivery unit 51 including a cylinder 52having an inlet aperture 5200Iformed with a shank 521, a curved neck,522. having a passage 523 therethrough, a semispherical socket 5220 at,the forward end of the said curved neck 522 at the endof the saidpassage 523 therethrough, anda T-slide 524 at the top of the said curvedneck 522. The said molten metal delivery unit 51 also includes a piston53 reciprocatingly fit in the cylinder 52 thereof, the said' piston 53having horizontal slots 530 therein to permit gripping the said piston53 by the fingers 242 on the depending arms 241 of the bifurcated cageelement 24. Obviously, with such reversal of the cylinder and piston,the embodiment of the molten metal pressureunit 51 shown in Figs. 13 and14 may readily be substituted for the embodiment of the molten metalpressure unit 11 shown in Figs. 11 and 12 and elsewhere throughout thedrawings.

Although but a single embodiment of the invention and alternateconstruction of several elements thereof have been disclosed anddescribed in detail, it is obvious-that many changes maybe made in thesize, shape, arrangement and specific details of the various elements ofthe invention without departing, from the spirit and scope thereof asdefinedbythe appended claims.

I claim:

1. In a die casting machine including a frame having a die mountedtherein, a molten metal pot and a nozzle having a passage therethroughthrough which molten metal is injected into said die, pressure chambermeans for injecting said molten metal into said die including a moltenmetal pressure delivery unit consisting of a cylinas} and a piston, apower actuated reciprocable. element fined tosaidlmachine frame, meanssuspending said cylins der in, dependingrelationship in. said. metal.notirom. said.

power actuated element, for, reciprocation, thereby,,, means. suspendingsaid piston loosely from said. machine frame, the said molten metaldelivery unit having a continuous,

passage through its cylinder and piston communicating, between saidmolten metal pot and said nozzle,,resilient frame holding said pistonand nozzle immovable during the injection cycle of operationof the diecasting machine.

2. In a die castingmachine includinga frame having;

a die mounted therein, a molten metal, pot and-.a nozzle having apassage theretliroughv through which molten metal is injected into saiddie, a pressure chamber, means for injecting said molten, metal into,said' die, including a moltenmetal] pressure delivery unit.consistingrof, a. cylinder and a piston, power means fixed. to saidmachine. frame having a reciprocable element, means suspending, saidmolten metal delivery unit from said machine frame with one of saidcylinder and piston in loosely depending relationship therefrom anddisposed against, said nozzle and the other disposed in saidv moltenmetal and removably coupled to the reciprocable. element, of said powermeans. for movement therewith, the saidmolten metal delivery unit,having a continuous. passage. therethrough communicating, between .said,molten. metal pot, and said nozzle, resilientmeans constantly urgingsaidsuspended one of said cylinder and piston of said, molten metal d'elivery unit in pressure contact against said nozzle. and said nozzle, inpressurecontact; against said die, and means releasably fixingthe saidloosely suspended one, of said.

cylinder and piston of said molten, metal pressure delivery unit to saidmeans suspending, it from said machine frame.

3. In a die casting machine including a frame anda die mounted therein,a molten. metal pot and a, nozzlehaving a passage therethroughthroughwhich molten metal is injected into said die, pressure chambermeans for injecting said molten. metal into said die including a, moltenmetal pressure delivery unit consistingof a cylinder and a piston, powermeans, fixed. to said. machine.

frame having a reciprocating element suspending, one of said cylinderand piston of saidmolten metal delivery unit therefrom, the other ofsaid cylinder and pistonof saidmolten metal delivery unit beingtlooselysuspended from said machine frame and disposed against said nozzle, thesaid molten metal delivery unit having a continu: ous passagetherethroughand communicating between said molten metal potand saidnozzle, resilient means constantly urging said element, of molten metaldelivery unit suspended loosely from said machine frame into pressureengagement with said nozzle and said nozzle into pressure engagementwith said die, and means releasably fixing the said loosely suspendedelement of the molten metal delivery unit to its suspension means, whereby to maintain said molten metal delivery element, said' saidreciprocable element removably and slidably sus-' pending said cylinderin depending relationship in said metal pot, means slidably; suspendingsaid piston loosely from said machine frame,,the saidmoltenmetaldeliveryunit having a continuous passage thrhugh its. cylinderand asrgiie pistoncommunicating between said molten metal pot and said nozzle, resilientmeans constantly urging said piston of the molten metal delivery unit inpressure contact against said nozzle and said nozzle against said die,and wedge means adapted to engage said piston of said molten metalpressure delivery unit releasably fixing said piston with respect tosaid means suspending it from said machine frame.

5. In a die casting machine including a frame having a die mountedtherein, a molten metal pot and a nozzle having a passage therethroughthrough which molen metal is injected into said die, pressure chambermeans for injecting said molten metal into said die including a moltenmetal pressure delivery unit consisting of a cylinder and a piston, apower actuated reciprocable element fixed to said machine frame, meansconnected to said reciprocable element. removably and slidably sus-vpending said cylinder in depending relationship in said metal pot, meansslidably suspending said piston loosely from said machine frame, thesaid molten metal delivery unit having a continuous passage through itscylinder and piston communicating between said molten metal pot and saidnozzle, resilient means constantly urging said piston of the moltenmetal delivery unit in pressure contact against said nozzle and saidnozzle against said die, and wedge means movable within said meansslidably suspending said piston of said molten metal pressure deliveryunit loosely from said machine frame releasably locking the said pistonwith respect to said means suspending it from said machine frame, andmeans for moving said wedge means into and out of its piston engagingposition.

6. In a die casting machine including a frame having a die mountedtherein, a molten metal pot and a nozzle having a passage therethroughthrough which molten metat is injected into said die, pressure chambermeans for injecting said molten metal into said die including a moltenmetal pressure delivery unit consisting of a cylinder and a piston, amounting block fixed to the machine frame, a power element fixed to saidmachine frame including a ram extending downwardly therefrom, meansconnected to said ram removably and slidably suspending said cylinder insaid metal pot, the said mounting block having a T-slot at the bottomthereof, a T-head on said piston slidably suspending said piston looselyfrom said mounting block at the said T-slot therein, the said moltenmetal delivery unit having a continuous passage through its cylinder andpiston communicating between said molten metal pot and said nozzle,resilient means constantly urging said piston of molten metal deliveryunit into pressure contact against said nozzle and said nozzle intopressure contact with said die, a second T-slot in said mounting blockabove said first mentioned T-slot and communicating therewith, and wedgemeans slidable in said second T-slot engaging the T-head of said pistonof said molten metal pressure delivery unit releasably fixing saidpiston with respect to said mounting block and said machine frame.

7. In a die casting machine including a frame having a die mountedtherein, a molten metal pot and a nozzle having a passage therethroughthrough which molten metal is injected into said die, pressure chambermeans for injecting said molten metal into said die including a moltenmetal pressure delivery unit consisting of a cylinder and a piston, amounting block fixed to the machine frame, a power element fixed to saidmachine frame including a ram extending downwardly therefrom, meansconnected to said ram removably and slidably suspending said cylinder insaid metal pot, the said mounting block having a T-slot at the bottomthereof, a T-head on said piston telescoped in said T-slot of saidmounting block slidably suspending said piston loosely therefrom, thesaid molten metal delivery unit having a continuous passage through itscylinder and piston communicating between said molten metal pot and saidnozzle, resilient means constantly urging said piston of molten metaldelivery unit into pressure contact against said nozzle and said nozzleinto pressure contact with said die, a second T- slot in saidmountingblock above said first mentioned T- slot and communicating therewith,and wedge means slidable in said second T-slot engaging the T-head ofsaid piston of said molten metal pressure delivery unit releasablylocking said piston with respect to said mounting block and said machineframe, and means urging said wedge means into locked position duringinjection of molten metal by said molten metal pressure delivery unit.

8. A die casting machine pressure chamber as claimed in claim 7 whereinthe said means for urging the said wedge means into and out of lockedposition consists of j a hydraulic cylinder including a ram connected tosaid wedge means, and means mounting said hydraulic cylinder on and inspaced relationship outwardly from said frame including a ram extendingdownwardly therefrom,

means connected to said ram removably and slidably suspending saidcylinder in said metal pot, the said mounting block having a T-slot atthe bottom thereof, a T- head on said piston telescoped in said T-slotof said mounting block slidably suspending said piston looselytherefrom, the said molten metal delivery unit having a continuouspassage through its cylinder and piston communicating between saidmolten metal pot and said nozzle, a pair of anchor bars extendingoutwardly from said frame, leaf spring means fixed on said anchor barsconstantly urging said piston of molten metal delivery unit intopressure contact against said nozzle and said nozzle into pressurecontact with said die, a second T-slot in said mounting block above saidfirst mentioned T-slot and communicating therewith, and wedge means insaid second T-slot engaging the T-head of said piston of said moltenmetal pressure delivery unit releasably fixing said piston into itsposition with respect to said mounting block and said machine frame towhich it is spring urged by said leaf spring means.

10. In a pressure chamber for a die casting machine including a framehaving a die mounted thereon, a molten metal pot and a nozzle having apassage therethrough communicating with said die, said pressure chambermeans comprising a molten metal pressure delivery unit including acylinder and a piston mounted therein, the

-said molten metal pressure delivery unit having a passage therethroughcommunicating between said molten metal pot and said nozzle, suspensionmeans floatingly mounting said delivery unit in depending relationshipfrom said machine frame including power means adapted to cause saidcylinder and piston to deliver molten metal from said molten metal potto said nozzle, means constantly urging said delivery unit in pressurecontact with said nozzle and said nozzle in pressure contact with saiddie, and wedge means mounted in said suspension means for anchoring saiddelivery unit in said pressure position prior to any die castingoperation by said pressure chamber means after heating of the moltenmetal delivery unit, the said suspension means, delivery unit and wedgemeans presenting large flat areas of contact therebetween.

1,944,199 Tischler Jan. 23, 1934 Halward Jan. 8, 1952'

